Labour has tabled a motion to debate the Benn bill in the Lords on Thursday.
Photograph: Parliament live

Conservative peers attempting to thwart Hilary Benn’s Brexit delay bill have been described as childish and irresponsible for trying to filibuster its passage through the House of Lords.

Brexit-backing Tory peers tabled more than 100 amendments to a motion put down by Labour leader in the Lords, Angela Smith, to ensure time is given to debate the bill and that it is completed by 5pm Friday.

Around 20 Tory peers said it was not fair to have their order paper ripped up to accommodate debate and a vote on legislation. They also objected to having a time limit assigned to the debate, which is not customary in the Lords.

Michael Forsyth was among the most vocal, complaining that Lady Smith’s proposal to give MPs up to 14 hours to complete the passage of the Benn bill in the Lords had driven “all other business off the agenda” while Nicholas True dramatically described the motion as a “dagger in my heart”.

The Liberal Democrat leader in the Lords, Dick Newby, said on the slew of amendments: “This is not even a subtle attempt at wrecking, it’s complete straightforward wrecking. It’s a very childish and irresponsible strategy.”

Among the peers to table “wrecking” amendments were the former Conservative leader Michael Howard, Michael Dobbs, and the party’s former deputy leader Peter Lilley. Many of them asked for precedence in the timetable to be given to a raft of their private members’ bills, ranging from legislation on bat habitation to land drainage, local elections, medical records and marriages taking place in a chapel.

None are expected to pass because Labour and the Lib Dems have a majority in the Lords, but the time involved to hear the raft of Tory amendments meant their colleagues were forced to sit late into the night, with peers bringing sleeping bags to work to try to catch a nap between votes. Smith’s time-limiting motion can only be voted on once all the amendments have been heard.

A Labour source said Tory attempts to filibuster the motion at this stage were intended to push the time available to discuss and vote on Benn’s bill perilously close to Monday 9 September, the date when Boris Johnson threatened to prorogue parliament, effectively scuppering the bill’s chance at royal assent.

It is understood that the Conservative peers had set up a rota to make sure there were enough peers around during the votes at different times of the evening.

“Our side are really ready for this though,” said the Labour source. “For some it’s taking them back to the all-night sittings of the 1970s in the Commons.”

It is expected that peers will also be requested to sit at the weekend to ensure the bill passes all its stages in time for Monday.

Lord Newby said: “We do hope the [Tories] give up. It’s OK doing this at 3pm in the afternoon, but at 5am the following day … The government here has time on its side, but ultimately we have the numbers.”

Smith said she had tabled her motion to make sure the Conservatives did not use their peers to scupper the legislation. She told the Lords: “We should abide by the principle of the primacy of the House of Commons. We are aware of a deliberate attempt to filibuster the bill, and I don’t think filibustering is in the best interests of the house.”